3 A, 30 V switching envelope for medium-current loads
The 2SD882 is a general-purpose NPN transistor rated for 3 A continuous collector current and a 30 V collector-emitter breakdown — this puts it in the sweet spot for driving relays, solenoids, small DC motors, and linear regulators where the load current stays under 2 A with headroom for inrush. At the full 3 A load, the Vce(sat) is 1.1 V max with 150 mA base drive — that 3.3 W conduction loss at 3 A needs a heatsink on the TO-126 tab; without one the junction hits 150 °C fast and the safe operating area shrinks. The 100 MHz transition frequency means it can handle PWM up to a few hundred kHz in switching applications, though the storage time in saturation will limit the practical switching speed — this is a transistor designed for saturated switching, not RF.
Gain margin and what it means for the base drive
Minimum DC current gain of 100 at 100 mA, 2 Vce means a 30 mA base current saturates a 3 A collector load — that is a forced beta of 100, which leaves the transistor in hard saturation with low Vce(sat). If you drive the base with a microcontroller GPIO through a 1 kΩ resistor from 5 V, the available base current is about 4 mA — that saturates up to 400 mA collector current at the minimum hFE, but at 3 A you need the full 30 mA base drive, so a driver transistor or a Darlington pair is required.
Package and thermal reality
The TO-225AA / TO-126-3 package (SOT-32) is a through-hole tab-mount — the collector is internally connected to the metal tab, so the tab must be electrically isolated from the heatsink or the heatsink must be at the collector potential. Maximum power dissipation is 12.5 W, but that figure assumes the case is held at 25 °C — in still air with no heatsink, the real dissipation is closer to 1–2 W before the junction hits 150 °C.
Lifecycle and compliance
STMicroelectronics lists the 2SD882 as Active — no end-of-life notice, no last-time-buy window. It remains a current-production part suitable for both new designs and repair of existing BOMs. ROHS3 compliant — no restricted substances above the threshold limits, which covers global shipping requirements including EU RoHS and China RoHS.